* {
    margin: 0;
    padding: 0;
}
ul, ol {
    list-style: none;
}
li {
    float: left;
}
.xk {
    width: 400px;
    height: 250px;
    overflow: hidden;
    margin: 0 auto;

    position:relative;
}
.imgs {
    position: absolute;
    transition-duration: 1s;
}
.imgs li {
    float: left;
}
.yuandian {
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    bottom: 0;
}
.yuandian li {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    margin: 0 5px;
    background-color: orchid;
}
.left {
    position: absolute;
    left: 5px;
    top: 50%;
    transform: translateY(-50%);
    padding: 5px;
}
.right {
    position: absolute;
    right: 5px;
    top: 50%;
    transform: translateY(-50%);
    padding: 5px;
}